BIOAVAILABILITY AND TOXICOKINETICS OF POLYCYCLIC AROMATIC-HYDROCARBONS SORBED TO SEDIMENTS FOR THE AMPHIPOD PONTOPOREIA-HOYI

The accumulation kinetics, by the benthic amphipod, Pontoporeia hoyi, were measured for sediment-associated, selected polycyclic aromatic hydrocarbons (PAHs) and 2,4,5,2′,4′,5′- hexachlorobiphenyl (HCB). The kinetics data suggest that uptake occurs largely via the sediment interstitial water and is kinetically controlled by desorption from sediment particles and dissolved organic matter. Assimilation from ingested material may be significant for the more strongly sorbed compounds such as benzo[a]-pyrene and HCB. The desorption rate of contaminants from the sediment matrix appears to determine whether the major sediment contaminant source is interstitial water or ingested particles. Bioavailability of sediment-sorbed contaminants declined as the contact time between the sediment and contaminant increased. A conceptual model to describe accumulation of organic contaminants from sediments is described.